When was the Digital Delay in Record Cutting First Introduced?

Just curious

when was the digital delay used in cutting vinyl first introduced?

Looking for a definitive year in which I can assume a LP is all-analog.

Please no digital v. analog debates

Please no "vinyl from digital can sound great" comments

Just looking for a specific date.

 

bump

 

i did some research and found little info, it seems like the Ampex ADD-1 was the first used and according to this site ( http://mixonline.com/mag/audio_masterfonics/ ) Masterfonics was the first to use it in 1973, but from most of the info i read it seems as if it was not until the early 80's that the Digital Delay Line was used commonly used for vinyl production.

 

Thanks!

 

It would be a good idea to explain why the digital delay line is commonly used in vinyl cutting these days:

But first, a disclaimer: Although I have about 15 years experience as a mastering engineer, I have never cut vinyl. My knowledge of the process is very much second hand. With that said, I will do my best. Please feel free to add any corrections, if necessary. So...

When a master lacquer is cut, the engineer must do the entire LP side at once, without stopping. If (when) a mistake is made with levels, EQ, etc, the lacquer is discarded, and the engineer starts over with a new blank. This gets expensive.

It is necessary for the engineer to monitor the program before it is cut, so that changes in level and EQ can be anticipated and adjusted for in time. However, the cutting stylus itself cannot be used for monitoring, as this signal is too late in the chain. (sound has already been recorded on the lacquer before it can be played back. Too late for the engineer to make any changes.)

Therefore, it is necessary to have some kind of "early playback" so that the engineer can make changes in time. In the past, custom analog mastering decks had a "preview head" mounted in the tape path, usually on the left side of the deck plate, near the supply reel. The tape path was modified with extra rollers and guides so that the tape would pass over the preview head (one second or so) before it got to the "normal" playback head for cutting. Quite a complex system to allow the engineer to monitor the signal before making the cut.

Keep in mind that a "normal" pro half-track deck may cost between 10 and 15 grand. Now add the cost of the custom mods and the preview head. Add in the popularity of 30 ips mastering, which complicates the tape path further, in order to get enough delay time between the preview and playback heads. Add in the rise of digital technology, and it wasn't long before some bright soul found an easier way to delay the signal, before sending it to the cutting stylus.

I would guess that the use of a digital delay line in cutting vinyl was common by the mid-1990s, as vinyl became a small-market niche product, and boutique labels no longer had access to custom mastering decks and other tools of the major-label process.

To the best of my knowledge,

 

Once a digital step is added, I don't understand why anyone would bother with real time eq and level adjustments. Why not just convert to digital, adjust in the DAW and then hit play?

 

I never understood this.

There is a pretty easy way to get a preview without using delay. Simply use another machine with a copy on it, start it early and use it for preview. Getting on the fly sync (with delay) may not be so easy, but I'm not sure how precise it has to be to get the job done.

 

I understand on the Joe Jackson BODY AND SOUL album they used a 4 track digital machine for the final stereo master, with the entire album recorded twice on the tape, offset by the required time interval. One pair of tracks fed the preview/variable pitch control system, the other fed the program signal to the cutting chain.

 

There's a fascinating discussion here about early digital that quickly derails to a good bit of info about the DDL. I also found the DDL patent!